KR20020033198A - Search method and receiving apparatus in cdma mobile communication receiving scheme - Google Patents

Abstract

Two kinds of user-defined navigators, namely narrow search range navigators (3, 4) and wide search range navigator (5), are set up and used from a plurality of navigator groups according to two kinds of multipath features at the mobile station, This makes it possible to search efficiently with high accuracy and reduced hardware and software size.

Description

SEARCH METHOD AND RECEIVING APPARATUS IN CDMA MOBILE COMMUNICATION RECEIVING SCHEME}

1. Technical Field

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous acquisition search method and a receiving apparatus in a reception method of a code division multiple access (CDMA) mobile communication system. The present invention relates to a synchronization acquisition search method and a receiving device using a plurality of searchers in which a search range is arbitrarily set.

2. Background Technology

Recently, much attention has been paid to a CDMA cellular telephone system in which spread spectrum processing of a carrier is performed by using pseudo random code as a spreading code, and the pattern and phase of a code sequence of spread signals are multiplexed. Is being changed to allow.

In this CDMA cellular telephone system, the correlation start position of the received spread signal must be determined at high speed. Once this initial synchronization is obtained, control needs to be performed to always keep the synchronization for correlation calculations by continuing to match chip timing with path jitter variations induced in the radio channel.

In a typical mobile communication system, the effects of multipath fading pose serious problems. The CDMA scheme uses the RAKE reception scheme to use such multipath positively and effectively. This RAKE reception scheme utilizes a plurality of fingers for performing receive processing and a searcher for generating receive timing according to a plurality of multipaths. After receive processing, the generated signal is synthesized.

As described above, a searcher is used to perform synchronous acquisition of the received signal and to obtain the reception timing from the delay distribution of the multipath.

7 illustrates the concept of a multi-purpose searcher describing a conventional search method. Referring to FIG. 7, the received signal 1 is sent to the plurality of searchers 70 to 72 through the switching device 2, and one searcher is assigned to each of the users 13 to 15. For example, the searcher 70 is assigned to the user # 0 (13), the searcher 71 is assigned to the user # 1 (14), and the searcher 72 is assigned to the user # 2 (15).

8 shows an overall configuration of a receiving apparatus using a conventional searching method. 8 shows only a portion corresponding to one user. Referring to FIG. 8, a radio signal propagating through a radio channel is received by the receiver 20 through an antenna. This received signal is converted into a digital signal by an analog / digital converter 21 connected to the output stage of the receiver 20, and becomes a baseband signal. This signal is sent to the multipath processing unit 80. In the multipath processing section 80, an input digital signal (baseband signal) is sent to the plurality of finger sections 81 which perform processing for each of the plurality of receive paths, and to the searcher section 82 which generates the reception timing. Then, the finger portion 81 performs receive processing in accordance with the reception path timing that is the output from the searcher portion 82.

The received signal output processed by the finger portion 81 is sent to the RAKE combining portion 23 for synthesis. The generated signal is sent to the signal processor 24 for decoding.

The operation of the conventional searcher 82 shown in FIG. 8 will be described below with reference to FIG. In the conventional searcher section 82, the total cell radius is set to the search range 90. The entire delay profile 40 is searched by using a single searcher section 82.

Multipath in mobile communication has two characteristics:

(1) Multipaths occur in a relatively narrow range at fairly frequent intervals. This range does not change rapidly. Therefore, the search should be made in a narrow range.

(2) In mobile communication, a sudden change in the reception state necessarily occurs, for example when the mobile station moves into the shadow of a building. This phenomenon is called shadowing and does not happen very often. In this phenomenon, however, something suddenly occurs that the signal cannot be received at the previous reception timing, and the location at which the new path will appear is unknown. For this reason, the full cell radius must always be searched. In other words, multipath behavior in mobile communications includes the two opposing features described above.

3. Detailed description of the invention

(Problems to Solve Invention)

In conventional methods in which processing is performed by one type of searcher, deterioration in accuracy occurs as the hardware or software size of the searcher increases or processing delay increases.

It is therefore an object of the present invention to provide a searching method and a receiving apparatus in a CDMA mobile communication receiving method which exhibit higher accuracy than the prior art.

(Workaround for the problem)

According to the present invention, in order to achieve the above object, according to the characteristics of the two types of multipath described above, two types of searchers, ie, narrow-search-range searchers and wide searchers, among a plurality of searcher groups. Set up a wide-search-range explorer.

That is, in the CDMA mobile communication reception method according to the present invention, the discovery method and the reception device respectively search for a wide search range cell searcher and a plurality of multipaths for searching the entire cell radius among a plurality of searcher groups according to multipath conditions. It is characterized by assigning one or more narrow search range delay spread searchers corresponding to respective users.

More specifically, in a reception method of a CDMA mobile communication system composed of a receiver, an analog / digital converter, a controller, a plurality of searchers, a plurality of fingers, a RAKE synthesizer, and a signal processor, the control unit uses one cell searcher. To assign, set the search width offset value to 0 and set the entire cell radius to the search range.

In addition, to assign a delay spread searcher, the control unit determines the number of peak levels equal to or higher than a threshold value from the effective path timing information on the delay distribution of the output of the received signal from each search unit. Calculate to determine the number of delay spread seekers required. In addition, the control unit calculates a width of the peak level equal to or higher than the threshold from the effective path timing information to determine the search range of each delay search searcher. In addition, the control unit calculates the position of the start timing of the peak level equal to or higher than the threshold value from the effective path timing information to determine the start point of the search operation of each delay spread searcher. This prevents an increase in processing delays and makes it possible to search with reduced hardware and software size at an efficient and high accuracy.

If all the explorers are in use and the number of users increases or the multi-path increases and a new cell explorer or delay spread explorer should be allocated, the control releases the delay spread explorer that has the lowest impact on each user among the explorers that have already been assigned. (release). This makes it possible to realize more efficient use of the explorer.

In addition, the control unit calculates a center position corresponding to the sum of the partial energy information and the multiplication of the partial position information for a plurality of paths equal to or higher than a predetermined level for the delay distribution of the delay spread searcher, and the calculated position Control is performed to prevent the difference from deviating from the limit of the search range. This can suppress the search error accompanying a change in the position of the mobile station, thereby increasing the search accuracy.

4. Brief Description of Drawings

1 is a diagram illustrating the concept of a receiving apparatus for explaining a searching method according to the present invention.

2 is a block diagram showing the overall configuration of a receiving apparatus using a searching method according to the present invention.

3 is a block diagram showing a detailed configuration of a searcher unit using a search method according to the present invention.

4 is a view for explaining a searcher allocation operation using the search method according to the present invention.

5 is a view for explaining a search range movement operation using a search method according to the present invention.

6 is a flowchart illustrating the overall operation of the searcher using the searching method according to the present invention.

7 is a diagram illustrating the concept of a conventional searcher.

8 is a block diagram showing the overall configuration of a receiving apparatus using a conventional search method.

9 is a view for explaining the operation of the conventional searcher in FIG.

5. Best Mode for Carrying Out the Invention

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described with reference to an accompanying drawing.

In the present invention, the following two types of searchers are defined, and the following operating conditions are set to execute the following functions for each searcher.

(1) Cell Searcher: The search range is set to the full radius of the target cell. The search resolution is low and the time required for searching is long.

(2) Delayed spread searcher: A narrow search range in which one effective multipath can be received. The search resolution is high and the time required for searching is short.

1 shows a concept of a receiving apparatus used for explaining a search method according to the present invention. Referring to FIG. 1, the received signal 1 is sent to the plurality of searchers 3 to 12 through the switching device 2. One of the cell navigators 5, 10, and 12 and at least one of the delay navigators 3, 4, 6, 7, 8, 9, and 11 are assigned to each user.

For example, for user # 0 13 shown in FIG. 1, because the received signal is sent through different receive paths and includes two signals with different phases, that is, two multipaths occur, delay Spread searchers 3 and 4 are assigned to each multipath. In addition to the two delay spread searchers described above, one cell searcher 5 is searched for the user, which searches the entire radius of the cell regardless of the multipath condition.

For user # 1 14, since four multipaths occur in the received signal, delay spread searchers 6, 7, 8, and 9 are assigned to each multipath. In addition to the four delay spread searchers described above, a cell searcher 10 for searching the entire radius of the cell is assigned to the user.

For user # 2 15, since one multipath occurs in the received signal, delay spread searcher 11 is assigned to a single multipath. In addition, a cell navigator 12 searching for the full radius of the cell is assigned to the user.

As mentioned above, the number of multipaths varies depending on the received signal for each user. For this reason, for users affected by many multipaths, many delay spread searchers are allocated that are equal to the number of multipaths. For users affected by a small number of multipaths, a small number of delay spread searchers are assigned.

2 shows an overall configuration of a receiving apparatus using a searching method according to the present invention. 2 shows only a portion corresponding to one user. Referring to FIG. 2, a radio signal propagating through a radio channel is received by the receiver 20 through an antenna. This received signal is converted into a digital signal by an analog / digital converter (A / D) connected to the output stage of the receiver 20, and becomes a baseband signal. This signal is sent to the multipath processing unit 22.

In the multipath processing section 22, an input baseband signal is sent to a plurality of finger sections 26 and a plurality of searcher sections 27 for generating reception timing. For each of the plurality of receive paths, the corresponding searcher 27 obtains a correlation value level by shifting the despread timing of the baseband signal little by little, and obtains an optimal reception timing for the corresponding finger 26. Assign. For each of the plurality of receive paths, the corresponding finger portion 26 despreads the baseband signal at the receive timing assigned by the searcher portion 27, thereby performing detection processing.

The outputs from the finger portion 26 are sent to the RAKE combining portion 23 to add up to each other. The generated signal is sent to the signal processor 24 for decoding.

The operation of the searcher unit 27 is controlled by the control unit 25. This control operation is performed based on the following four input signals.

(1) P (i) input signal 60: i-th valid path timing information for the delay distribution of the received signal output from each search unit 27

(2) E (i) input signal 61: i-th effective path energy information of the received signal processed by each finger part 26 (field strength in the i-th effective path = Eb / Io)

(3) Q (U) input signal 62: the current reception quality (current frame error rate) of the signal output from the signal processing section 24 and associated with the user U and

(4) QoS (U) input signal 63: Quality of service required for user (U) and registered in system data (predetermined frame error rate)

More specifically, the control unit 25 generates a control signal in order to classify the searchers from the input signals into two types of function-specific searchers (cell searchers and delay searchers), and the setting state of the searchers. Change the control signal to keep it optimal.

FIG. 3 shows a detailed configuration of one of the searcher sections 27 shown in FIG. In this case, this searcher section will be described as one searcher section 31.

Referring to FIG. 3, the baseband signal 30 sent from the A / D converter 21 is a search width offset delay circuit 37 and a search, which are two types of delay circuits of the searcher 27. Along with the spreading code controlled by the delay circuit 36, it is input to each correlator 1 to n of the plurality of correlator 33 groups. Each correlator 1 to n performs despreading at slightly different reception timings from each other. Outputs from respective correlators of the plurality of correlators 33 groups are respectively input to adders 1 to n of the plurality of adders 34 groups. Each adder adds a correlation value the number of times it is assigned. The output from each adder of the plurality of adder 34 groups is input to the valid path determining unit 35. The valid path determining unit 35 searches for the summation correlation value for the reception timing with the high level (searches the peak), and determines whether to set the corresponding path as the valid path.

The effective path determiner 35 performs defensive processing to prevent frequent changes in the effective path assignment due to fluctuations in the level due to small changes in fading and reception timings, thereby enabling stable reception of signals. do. The determined reception path information is output as the peak timing signal 32, provided to the corresponding one of the finger portions 26, and also output to the controller 25 as the P (i) signal 60.

The control unit 25 performs the first searcher assignment operation based on the P (i) signal 60 which is the i-th valid path timing information for the delay distribution of the reception signal output from each searcher unit. On the basis of this effective path timing information P (i) signal 60, the control unit 25 determines the specific number of peak levels equal to or higher than the threshold value, the specific width of the peak levels, and the start timing of each peak level. Calculate the specific location, etc.

The controller 25 determines the number of delay spread searchers required from the number of peak levels equal to or higher than this threshold, calculates the search range control signal 64 from the width of the peak levels, and starts timing of each peak level. The search width offset control signal 65 is calculated from.

Spread code generator 38 generates a spread code to despread the baseband signal. This spreading code is provided to each correlator of a plurality of groups of correlators 33 through a search width offset delay circuit 37 and a search delay circuit 36, which are two types of delay circuits.

The search width offset delay circuit 37 determines the starting point of the search operation by delaying the spreading code by the search width offset amount based on the search width offset control signal 65. The search delay circuit 36 slightly delays the spread code input from the search width offset delay circuit 37 so that the despread timing of each correlator of the majority correlator 33 group differs from each other by a predetermined time interval. Further, the search delay circuit 36 determines the search range of each searcher section based on the search range control signal 64.

Hereinafter, a searcher assignment operation using the search method of the present invention will be described with reference to FIG. 4 shows a case for user # 0 13 in FIG. 1. The reference reception timing of the radio transceiver station BTS indicates propagation delay = 0 based on the reception timing of the BTS. For a received signal with delay distribution 40, the number of paths (number of valid paths) equal to or higher than the peak level threshold is two. In this case, the controller 25 assigns the set of searchers 5 to the cell searcher, and assigns the set of searchers 3 and 4 to the delayed spreading searchers 3 and 4 for each valid path.

The set of searchers 5 as the cell searcher sets the search width offset from 44 to 0 in order to set the search range 41 to the full radius of the cell. The set of searchers 3 as a delay spread searcher operates with a search width offset 45 and a search range 42 as shown in FIG. 4 to search the first path. Similarly, the set of searchers 4 as a delay spread searcher operates with a search width offset 46 and a search range 43 as shown in FIG. 4 to search for a second path.

The control unit 25 controls each searcher in this manner. Since the number of explorers is limited in hardware resources, if all explorers are in use, the number of users or multipaths must increase, and a new cell explorer or delay spread explorer must be assigned, the lowest impact on each user among the explorers already assigned. Delay spreading searcher is released.

In this case, the controller 25 calculates the degree of influence on each user of the assigned searcher based on the following three factors.

(1) QoS (U): Quality of service registered in system data and required for user U (predetermined frame error rate)

(2) Q (U): the current reception quality (current frame error rate) of the signal output from the signal processing unit 24 and the current reception quality (current frame error rate) in relation to the user U and

(3) E (ds): energy information in the effective path of the target delay spreading searcher (field strength in the effective path = Eb / Io)

If the DS is about the influence on the searcher already assigned to the user, and the DSmin is the minimum value of the DS, the minimum value DSmin is obtained by calculating Equation 1 given below for all the delay spreading searchers in all users.

DSmin = MIN [(QoS (U)-Q (U)) x E (ds)]

Applies to all U and ds.

The control unit 25 operates to release the delay spread searcher corresponding to DSmin, and assign the released searcher to a new user or multipath.

Hereinafter, a search range shift operation using the search method of the present invention will be described with reference to FIGS. 5A, 5B, and 5C. Defensive processing is performed for each searcher to prevent frequent changes in the allocation of valid paths due to variations in the level of the received signal due to minor changes in fading and reception timing. However, if the mobile station moves beyond this defense processing after the searcher is assigned, the delay distribution will change significantly and fall outside the search range of the searcher, resulting in a decrease in search accuracy.

Therefore, the control unit 25 obtains the center Pc of the delay distribution and controls the search range of the searcher in accordance with the positional change of the center Pc. First, the center Pc of the delay distribution is obtained by using Equation 2 based on the following three elements.

(1) N: number of paths equal to or higher than a predetermined level in the search range of the delay spread searcher (number of valid paths)

(2) P (i): i-th valid path position information for the delay distribution and

(3) E (i): i-th effective path energy information in the delay distribution (field strength in the i-th effective path = Eb / Io)

The center Pc of this delay distribution is composed of the center energy information PcE and the center position information PcW, and the center position information PcW of the center Pc is obtained from the following equation.

PcW = Pc ÷ PcE

The operation of changing the search range of the searcher to match the position variation of the center Pc is obtained by using Equation 4 based on the following factors.

(1) Wf_old: Search start position of delay spread explorer before change

(2) Wf_new: Search start position of delay spread explorer after change

(3) W: search range of delay spread explorer and

(4) α, β: constants (α <β)

if (PcW <(Wf_old + αW)) then Wf_new

= Wf_old-[Wf_old + (α + β) W / 2)-PcW]

else if (PcW> (Wf_old + β)) then Wf_new

= Wf_old + [PcW-(Wf_old + (α + β) W / 2)]

else then no change in search range

The above operation will be described with reference to FIGS. 5A, 5B, and 5C. 5A shows the relationship between the delay distribution 56 at the initial delay spread searcher allocation and the search range 50 of the delay spread searcher. Referring to FIG. 5A, the center position PcW 54 calculated from the total information obtained by multiplying the energy information and the position information of each of the paths 51, 52 and 53 equal to or higher than a predetermined level and summing each result together. Is assigned. Clearly, in the initial delay spread searcher assignment, the center position PcW 54 coincides with the center 55 of the threshold value 57 in the search range of the delay spread searcher, and the delay distribution 56 falls within the search range of the delay spread searcher. Corresponding. While the center position PcW 54 falls within the position range of the threshold value 57, the controller 25 does not activate the operation of changing the search range of the delay spread searcher.

FIG. 5B shows a case where the delay distribution 56 shifts to the left after the drawing is made because the mobile station has approached the radio station greatly. Referring to FIG. 5B, the center position PcW 54 of the delay distribution 56 shifts to the left beyond the position range of the threshold value 57 in the search range of the delay spread searcher. The controller 25 activates an operation of changing the search range of the delay spread searcher. The controller 25 controls the center position PcW 54, the value of PcW of the delay distribution 56 from the center 55, and the Wf_old + of the threshold value 57 in the search range of the delay spread search as shown in equation (4). The search range 50 of the delay diffusion searcher is shifted to the left by the value obtained by subtracting (α + β) W / 2. That is, the control unit 25 changes the search range of the delay spread searcher by subtracting the value from the value of the search width offset control signal 65 that controls the search width offset delay circuit 37.

Fig. 5C shows a case in which the mobile station shifts to the right after the drawing (after assignment of the description) because the mobile station is far from the radio station. Referring to FIG. 5C, the center position PcW 54 of the delay distribution 56 shifts to the right by more than the position range of the threshold value 57 in the search range of the delay spread searcher. The controller 25 activates the operation of changing the search range of the delay spread searcher. The control section 25 has a delay distribution as shown by the threshold value 57 Wf_old + (α + β) W / 2 from the center position PcW 54 in the center 55, the search range of the delay spread searcher, and equation (4). The search range of the delay spread searcher is shifted to the right by the value obtained by subtracting the PcW value of (56). That is, the control unit 25 changes the search range of the delay spread searcher by adding the value to the value of the search width offset control signal 65 that controls the search width offset delay circuit 37.

Hereinafter, the overall operation of the searcher using the search method of the present invention will be described with reference to FIG. 6.

Referring to Fig. 6, when a signal is received from a new user, the control unit 25 for the searcher is activated (step A1) to check whether there is an unused searcher that can be assigned to the user (step A2).

If there is no unused searcher, then the delayed spreading searcher, which exhibits the lowest degree of impact from the operation based on Equation 1, is released (step A3). When the unused searcher is prepared, the control unit 25 sets the available searcher as the delay spread searcher or the cell searcher (step A4). Therefore, search processing is performed by using this searcher, and a path is assigned to each finger (step A5).

The control unit 25 confirms the center position of the delay spread searcher to monitor whether the center position falls within the limit of the search range (step A6). If the center position falls within the threshold, the controller 25 keeps the search range unchanged. If the center position exceeds the threshold value, the control unit 25 moves the search range of the delay spread searcher by the operation based on the above-described equation (4) and FIGS. 5A, 5B, and 5C (step A7).

The control unit 25 monitors the multipath condition through the delay spread searcher and the cell searcher, and determines whether to assign the delay spread searcher to the user based on the multipath condition (step A8). As in the operations from step A2 to step A4, it is checked whether there is an unused searcher that can be assigned to the user when adding the delay spread searcher (step A9), and if there is no unused searcher, from the operation based on Equation 1 above. The delay spread searcher exhibiting the lowest degree of influence obtained is released (step A10), and the available searcher is set to the required delay spread searcher (step A11), thereby adding a delay spread searcher.

Finally, the control unit 25 monitors the end of communication (step A12). While the communication continues, the flow returns to step A5 to continue the search processing, and a series of operations are repeated. After the communication ends, this operation is terminated (step A13).

As described above, according to the characteristics of the multipaths generated according to the present invention, an increase in processing delay is achieved by using two types of explorers among multiple explorer groups for each user, that is, a combination of a narrow search range explorer and a wide search range explorer. Can be prevented. This makes it possible to provide an efficient search method that suppresses the increase in hardware and software size.

When all the searchers are used, the control unit identifies the delayed spreading searcher showing the lowest effect on each user among the assigned searchers and releases the delayed spreading searcher, thereby enabling efficient use of the searcher.

In addition, the control unit obtains the center of the delay distribution and controls the search range of the searcher according to the change in the center position. As a result, it is possible to suppress the search error accompanying the change in the position of the mobile station and to increase the search accuracy.

Claims (10)

As a search method in a CDMA mobile communication system, One cell searcher for searching the entire cell with a wide search range, and one or more delay spread searchers having a narrower search range than the cell searcher, assigned to the received signal according to the multipath conditions of the received signal, A synchronous acquisition is performed on the basis of the signal. The method of claim 1, Each of the delay spread searchers is assigned to a readable multipath. As a search method in a CDMA mobile communication system, A receiver for receiving a received signal transmitted through a radio channel; An analog / digital converter converting the received signal into a digital baseband signal; A multipath processor having a plurality of searchers and a plurality of fingers, and outputting a plurality of detection signals by processing the multipaths included in the baseband signal; A RAKE synthesis unit configured to add the detection signals and output a synthesized signal; A signal processor for synthesizing the synthesized signal; And A control unit for controlling the searcher unit is provided, The control unit may include: effective path timing information of a delay distribution of a received signal output from the searcher unit, valid path energy information of a received signal processed by the finger unit, and a current reception quality output from a signal processor and associated with the user Generate control signals for setting the plurality of searchers as two types of function specific searchers, a cell searcher and a delay spread searcher, based on four signals registered in system data and based on the quality of service required by the user. , And a control signal is changed to optimally maintain a set state of the plurality of searchers. The method of claim 3, wherein The control unit outputs a search range control signal and a search width offset control signal to one searcher so that the searcher operates as a cell searcher for searching the entire radius of the cell. Outputting a search range control signal and a search width offset control signal to the plurality of searchers so that the searcher operates as a delayed spreading searcher respectively searching for a plurality of multipaths, The searcher unit includes a plurality of correlator groups for receiving a new spreading code obtained by performing delay processing by a search width offset delay circuit and a search delay circuit with a baseband signal and performing despreading on a spread code from a spreading code generator. A plurality of adder groups for adding a correlation value output from the correlator group by the assigned number of times, and a valid path determination for searching for a reception timing having a high level from the correlation value after addition and determining whether a corresponding path is an effective path. Wealth, and The search width offset delay circuit controls the search start timing according to the search width offset control signal from the controller, and the search delay circuit controls the search range according to the search range control signal from the controller. Way. The method of claim 4, wherein The search range control signal for operating the searcher as the cell searcher sets a value equal to a cell radius as the search range, and the search width offset control signal for operating the searcher as the cell searcher sets 0 as an offset value. , The search range control signal for operating the searcher as the delay spread searcher sets the width of the peak level calculated from the effective path timing information for the delay distribution of the received signal as the search range, and sets the searcher as the delay spread searcher. And wherein the search width offset control signal for operating sets the start timing of the peak level calculated from the effective path timing information for the delay distribution of the received signal as an offset value. The method of claim 4, wherein While all searchers are in use, if the number of users or multipath needs to be increased so that a new cell searcher or delay spread searcher needs to be assigned, the control unit is associated with the users and The numerical value calculated by multiplying the difference value obtained by subtracting the current reception quality value output from the signal processing unit from the service quality value required for the user and registered in the system data, and multiplying the energy information value in the effective path of the target delay spreading searcher. And release the delayed spread explorer in use, which is the lowest of the values, and assign the released explorer to a new user or multipath. The method of claim 4, wherein The controller is configured to calculate a sum of the multiplied values by adding a value obtained by multiplying the energy information portion and the location information portion of a plurality of paths of a predetermined level or more on the delay distribution of the delay spread searcher, calculating the position information of the sum, Compare the location information with a threshold of the search range of the delay spread searcher, and if the comparison result exceeds the threshold of the search range, change the search range of the searcher, thereby centering the search range And control to match a position with a position in the sum. In the receiving device in the CDMA mobile communication scheme, And a multipath processing unit for allocating one or more delayed searchers having a narrower search range than the cell searcher according to a multipath condition of a received signal. And a multipath processing unit performs synchronization acquisition based on signals obtained from each searcher. In the receiving device in the CDMA mobile communication scheme, A receiver for receiving a received signal transmitted through a radio channel, an analog / digital converter for converting the received signal into a digital baseband signal, a plurality of searchers and a plurality of fingers, and a multipath included in the baseband signal. A multipath processing unit for outputting a plurality of detection signals to output a plurality of detection signals, a RAKE synthesis unit for outputting a synthesized signal by adding the detection signals, a signal processing unit for synthesizing the synthesized signals, and a control unit for controlling the searcher unit; , The control unit may include the effective path timing information of the delay distribution of the received signal output from the searcher unit, the effective path energy information of the received signal processed by the finger unit, a current reception quality related to a user and output from the signal processor, And based on four signals required for the user and based on the quality of service registered in the system data, generating control signals for setting the plurality of searchers into two types of function specific searchers: a cell searcher and a delay spread searcher. And means for changing a control signal to optimally maintain a set state of the plurality of searcher units. A CDMA receiving apparatus, which is a receiving method of a CDMA mobile communication system, by which the control unit searches one search unit for an entire radius of a cell. The control unit may include the effective path timing information of the delay distribution of the received signal output from the searcher unit, the effective path energy information of the received signal processed by the finger unit, a current reception quality related to a user and output from the signal processor, And based on four signals required for the user and based on the quality of service registered in the system data, generating control signals for setting the plurality of searchers into two types of function specific searchers: a cell searcher and a delay spread searcher. And means for changing a control signal to optimally maintain the set state of the plurality of searchers.